Impeded lung function in moulders and coremakers handling furan resin sand

Summary A total of 39 moulders and coremakers exposed to furan resin sand and 27 unexposed local controls were examined by lung-function tests before and after a work shift. In all, 28 of the subjects exposed to furan resin sand and the control group were evaluated by dynamic spirometry and nitrogen washout. The remaining 11 subjects exposed to furan resin sand were studied using both static and dynamic spirometry and the CO single-breath technique. The time-weighted average exposure to furfuryl alcohol was about 7 mg/m³, with peak values exceeding the present Swedish short-term exposure limit (40 mg/m³). The exposure to respirable dust and formaldehyde as time-weighted over the shift was < 2 mg/m³ and 0.4 mg/m³, respectively, in all groups. During the work shift studied, the 28 exposed subjects had more complaints of airway symptoms than did the controls, showing an average decrease of 0.21 in forced vital capacity but no fall in any other lung-function variable. The remaining 11 exposed subjects demonstrated a post-shift decrease in total lung capacity. The results indicate an acute restrictiveness induced by exposure to furan resin sand, but the underlying mechanism is unclear. Chronic impairment of lung function was not observed.     

Determinants of dust and endotoxin exposure of pig farmers: Development of a control strategy using empirical modelling

Personal exposure to dust and endotoxin was measured among 198 Dutch pig farmers. For each participant 8-h measurements were made on 2 days, one in summer 1991 and one in winter 1992. Mean time-weighted average (TWA) exposure to dust was 3.0 mg m⁻³ (arithmetic mean, range 0.3–27 mg m⁻³) and mean TWA exposure to endotoxin was 130 ng m⁻³ (arithmetic mean, range 6–1503 mg m⁻³). Empirical statistical modelling was applied to identify activities and farm characteristics associated with exposure. In a multiple least-squares regression analysis, aspects of hygiene and feeding were major characteristics associated with dust exposure. Flooring and feeding were predominant characteristics explaining variation in endotoxin exposure. Activities performed frequently, like feeding and controlling, cleaning activities and activities in which very active animals were involved, such as teeth cutting and ear tagging, were associated with exposure to dust and endotoxin. The models were used to set priorities for the development of control measures to eliminate the dust and endotoxin hazard of pig farmers.     

Acute lung function changes and low endotoxin exposures in the potato processing industry

Work-related respiratory symptoms, acute lung function changes and personal endotoxin exposure were studied in 61 workers from a potato processing plant. According to their job title mean endotoxin exposure level, workers were divided into low (AM = 21 EU/m³) and high (AM = 56 EU/m³) exposure categories. Shortness of breath and chest tightness during work were reported by 18% and 16% of the workers, respectively, mainly in the low endotoxin exposure category. A total of 148 across-shift lung function changes were measured during three consecutive afternoon shifts. The mean FEV₁ and MMEF showed a decrease over the work shift, being largest on the first working day after a 3-day absence from work. Workers exposed to high endotoxin levels showed a larger across-shift decrease in lung function than workers exposed to low endotoxin exposures, the effect being most pronounced on the first day after a 3-day absence from work. At the start of the second work shift, FVC, FEV₁ and MMEF were lower than at the start of the first work shift. This difference was larger for high exposed workers. High exposed workers with work-related respiratory symptoms showed an 8–10% across-shift change in FVC, FEV₁ and MMEF. We conclude that significant across-shift decreases in lung function of potato processing workers is related to endotoxin exposure levels above 53 EU/m³ over 8 hr. Am. J. Ind. Med. 33:384–391, 1998. © 1998 Wiley-Liss, Inc.     

Respiratory dysfunction in swine production facility workers: Dose-response relationships of environmental exposures and pulmonary function

Human respiratory health hazards for people working in livestock confinement buildings have been recognized since 1974. However, before comprehensive control programs can be implemented, more knowledge is needed of specific hazardous substances present in the air of these buildings, and at what concentrations they are harmful. Therefore, a medical epidemiological and exposure-response study was conducted on 207 swine producers using intensive housing systems (108 farms). Dose-response relationships between pulmonary function and exposures are reported here. Positive correlations were seen between change in pulmonary function over a work period and exposure to total dust, respirable dust, ammonia, respirable endotoxin, and the interactions of age-of-producer and dust exposure and years-of-working-in-the-facility and dust exposure. Relationships between baseline pulmonary function and exposures were not strong and therefore, not pursued in this study. The correlations between exposure and response were stronger after 6 years of exposure. Multiple regression models were used to identify total dust and ammonia as the two primary environmental predictors of pulmonary function decrements over a work period. The regression models were then used to determine exposure concentrations related to pulmonary function decrements suggestive of a health hazard. Total dust concentrations ? 2.8 mg/m³ were predictive of a work period decrement of ? 10% in FEV₁. Ammonia concentrations of ? 7.5 ppm were predictive of a ? 3% work period decrement in FEV₁. These predictive concentrations were similar to a previous doseresponse study, which suggested 2.5 mg/m³ of total dust and 7 ppm of NH₃ were associated with significant work period decrements. Therefore, dust ? 2.8 mg/m³ and ammonia ? 7.5 ppm should be considered reasonable evidence for guidelines regarding hazardous exposure concentrations in this work environment.     

Longitudinal changes in inflammatory markers in nasal lavage of cotton workers

Objectives: The aim of this study was to evaluate time-related changes in inflammatory markers in nasal lavage (NAL) in relation to endotoxin exposure and lung function changes. Methods: Endotoxin in cotton dust is well known to elicit proinflammatory mediators involved in acute or chronic respiratory inflammation due to cotton dust. We applied nasal lavage as well as lung function and exposure measurements in a small group (n=11) of cotton workers during 6 weeks of observation (after 2 weeks free of exposure). Several inflammatory markers in NAL, such as interleukin 8 (IL-8), IL-6, and downstream mediators, including soluble tumor necrosis factor receptor 75 (sTNF-R75) and soluble intercellular adhesion molecule 1 (ICAM-1), cell counts, marker of epithelial response (uric acid), and marker of plasma exudation (albumin) were measured. Results: At the exposure levels examined in this study [cotton dust, geometric mean (GM) = 1.10mg/m³; endotoxin, GM = 2,869 EU/m³], several inflammatory markers in NAL such as IL-8, sTNF-R75, and albumin tended to increase through the measurement period with increasing airborne endotoxin concentration (in six workers who had paired measurements in weeks 1 and 6). Although no statistical significance was reached, airborne endotoxin exposure and all inflammatory markers in NAL were relatively higher in cotton workers with a 6-week lung function decrease. Conclusion: The data suggest that inflammatory markers in NAL are associated with repeated airborne endotoxin exposure. Received: 17 January 1997 / Accepted: 10 July 1997     

Short term changes in lung function, leukocytosis in blood, and lachrymal fluid among bacterial single cell protein workers after an episode with high exposure to endotoxins

Aims: To study possible effects of endotoxin exposure among bacterial single cell protein workers on pulmonary function, blood parameters, and lachrymal fluid before and after a work shift. Methods: The study included 23 men and five women who were examined at the start and at the end of a work shift. Most workers performed a task with unusually high exposure levels. Twelve of the workers were re-examined the day after. The workers were divided into three exposure groups: production workers with the highest assumed exposure levels (n = 18), engineers (n = 5), and clerks (n = 2). The median endotoxin level during a work shift was 34000 EU/m³ in the high exposure group (range 3300–89000 EU/m³ ), 11000 EU/m³ (range 350–27000 EU/m³) among the engineers, and 180 EU/m³ (range 60–300 EU/m³) for the clerks. The workers answered a questionnaire about work related symptoms. Assessment of lung function included dynamic lung volumes and flows. The blood analysis included cell count of leukocytes and mediators of inflammation, fibrinogen, interleukin-6 (IL-6), D-dimer, and C-reactive protein (CRP). Cells in lachrymal fluid were counted with a microscope. Results: The forced vital capacity (FVC) changed significantly (p<0.05) from 5.34 l (SD 0.9) to 5.25 l (SD 0.9) and forced expired volume in one second (FEV1) from 4.15 l (SD 0.7) to 4.07 l (SD 0.7) during the work shift. The leukocytes increased significantly (p<0.05) from 6.9 10⁹/l (SD 1.2) to 7.7 10⁹/l (SD 1.5) and IL-6 from 1.5 ng/l (SD 0.6) to 3.31 ng/l (SD 2.7). Except for fibrinogen, which had a borderline increase and PEF that decreased, the parameters were normalised the day after. Four of the workers had an increase of neutrofile granulocytes in the lachrymal fluid during the shift. There was a significant association between the endotoxin concentration and decrease of FEV1 despite the use of powered respirators. Conclusions: During a work shift with unusual high levels of endotoxins at a plant manufacturing bacterial single cell protein the results show that FVC and FEV1 were reduced. Mediators of inflammation increased along with leucocytosis in blood and lachrymal fluid among the workers.     

Respiratory health effects of occupational exposure to charcoal dust in Namibia

Background: Charcoal processing activities can increase the risk of adverse respiratory outcomes.

Objective: To determine dose–response relationships between occupational exposure to charcoal dust, respiratory symptoms and lung function among charcoal-processing workers in Namibia.

Methods: A cross-sectional study was conducted with 307 workers from charcoal factories in Namibia. All respondents completed interviewer-administered questionnaires. Spirometry was performed, ambient and respirable dust levels were assessed in different work sections. Multiple logistic regression analysis estimated the overall effect of charcoal dust exposure on respiratory outcomes, while linear regression estimated the exposure-related effect on lung function. Workers were stratified according to cumulative dust exposure category.

Results: Exposure to respirable charcoal dust levels was above occupational exposure limits in most sectors, with packing and weighing having the highest dust exposure levels (median 27.7 mg/m³, range: 0.2–33.0 for the 8-h time-weighted average). The high cumulative dust exposure category was significantly associated with usual cough (OR: 2.1; 95% CI: 1.1–4.0), usual phlegm (OR: 2.1; 95% CI: 1.1–4.1), episodes of phlegm and cough (OR: 2.8; 95% CI: 1.1–6.1), and shortness of breath. A non-statistically significant lower adjusted mean-predicted % FEV1 was observed (98.1% for male and 95.5% for female) among workers with greater exposure.

Conclusions: Charcoal dust levels exceeded the US OSHA recommended limit of 3.5 mg/m³ for carbon-black-containing material and study participants presented with exposure-related adverse respiratory outcomes in a dose–response manner. Our findings suggest that the Namibian Ministry of Labour introduce stronger enforcement strategies of existing national health and safety regulations within the industry.     

Respiratory Hazards Associated with Exposure to Formaldehyde and Solvents in Acid-Curing Paints

Thirty-eight employees exposed to formaldehyde when working with acid-hardening lacquers and 18 nonexposed control persons employed at the same company were examined to determine lung function (spirometry and nitrogen washout), total immunoglobulin blood concentration, and work-related symptoms. The mean exposure to formaldehyde during an 8-hr workday was 0.40 mg/m³ air, and the mean exposure to peak values was 0.70 mg/m³. Mean exposure to solvents was low, i.e., approximately 1/10 of the hygienic effect. Eye, nose, and throat irritation was more common in exposed persons than in controls. Monday morning, after two exposure-free days, forced vital capacity (FVC) values were found to have declined by 0.24 L and forced expiratory volume in 1 sec (FEV_1.0) by 0.21 L, compared with normal values. There was a weak correlation between the individual concentration of IgG and decrease in FVC and FEV_1.0. No significant changes were noted in any other lung function variable before a workshift, and no lung function changes were noted over a full workshift. Deviations in FVC and FEV_1.0 values did not correlate to peaks or mean exposures or employment time.     

Respiratory Health of Plywood Workers Occupationally Exposed to Formaldehyde

This study was undertaken to enlarge our understanding of the adverse health effects of formaldehyde exposure in the workplace and community environment. The respiratory health status of 186 male plywood workers was evaluated by spirometric tests, respiratory questionnaires, and chest x-rays. Area concentrations of formaldehyde were measured in the work environment and found to range from 0.28 to 3.48 ppm. The average personal exposure was to 1.13 ppm of formaldehyde. Exposure to formaldehyde was associated with decrements in the baseline spirometric values, i.e., forced expiratory volume in 1 sec (FEV_(1.2) forced expiratory volume/forced vital capacity (FEV/FVC), and FEF_25%-75%, and with several respiratory symptoms and diseases, including cough, phlegm, asthma, chronic bronchitis, and chest colds. The results of the study support the hypothesis that chronic exposure to formaldehyde induces symptoms and signs of chronic obstructive lung disease.     

Respirable dust and silica exposure among World Trade Center cleanup workers

The cleanup effort following the destruction of the World Trade Center (WTC) was unprecedented and involved removal of 1.8 million tons of rubble over a nine-month period. Work at the site occurred 24 hr a day, 7 days a week and involved thousands of workers during the process. The Occupational Safety and Health Administration (OSHA) conducted personal and area exposure sampling during the cleanup of the site. Secondary data analysis was performed on OSHA air sampling data for respirable dust and silica from September 2001 to June 2002 at the WTC recovery site to characterize workers' exposure. Results for silica and respirable particulate were stratified by area and personal samples as well as job task for analysis. Of 1108 samples included in the analysis, 693 were personal and 415 were area. The mean result for personal silica samples was 42 μg/m³ (Range: 4.2–1800 μg/m³). Workers identified as drillers had the highest mean silica exposure (72 μg/m³; range: 5.8–800 μg/m³) followed by workers identified as dock builders (67 μg/m³; range: 5.8–670 μg/m³). The mean result for personal samples for respirable particulate was 0.44 mg/m³ (range: 0.00010–13 mg/m³). There were no discernable trends in personal respirable dust and silica concentrations with date.     

Protein accumulation in lung lavage fluid following ozone exposure

Accumulation of protein in lung lavage fluid was used as an indicator of pulmonary damage following exposure of guinea pigs to O₃. Exposure of animals to 510, 1000, or 1960 μg/m³ (0.26, 0.51, or 1.0 ppm) of O₃ for 72 hr resulted in significantly elevated levels of lavage fluid protein when compared to that of air controls. This effect was not observed in animals exposed to 196 μg O₃/m³ (0.10 ppm). When exposure time was reduced to 3 hr, the O₃-induced protein accumulation in lavage fluids was undetectable unless the time of lavage was delayed 10–15 hr following the exposure. Under these conditions, elevated protein content was seen in lung lavage fluids obtained from animals exposed to O₃ ranging from 510 to 1470 μg O₃/m³ (0.26-0.75 ppm) and a dose relationship between the amount of protein accumulation in the lung and the concentration of O₃ to which the animals were exposed was observed. Vitamin C deficiency did not enhance this O₃-induced lesion in guinea pigs. The dose relationship has also been confirmed by polyacrylamide gel electrophoresis of the lavage fluids. Lung lavage fluid protein content in animals exposed to 353 μg O₃/m³ (0.18 ppm) for 8 hr/day for 5 or 10 consecutive days was not different from that of air controls.     

Performance of prototype high-flow inhalable dust sampler in a livestock production facility

A high-flow inhalable sampler, designed for operational flow rates up to 10 L/min using computer simulations and examined in wind tunnel experiments, was evaluated in the field. This prototype sampler was deployed in collocation with an IOM (the benchmark standard sampler) in a swine farrowing building to examine the sampling performance for assessing concentrations of inhalable particulate mass and endotoxin. Paired samplers were deployed for 24 hr on 19 days over a 3-month period. On each sampling day, the paired samplers were deployed at three fixed locations and data were analyzed to identify agreement and to examine systematic biases between concentrations measured by these samplers. Thirty-six paired gravimetric samples were analyzed; insignificant, unsubstantial differences between concentrations were identified between the two samplers (p = 0.16; mean difference 0.03 mg/m³). Forty-four paired samples were available for endotoxin analysis, and a significant (p = 0.001) difference in endotoxin concentration was identified: the prototype sampler, on average, had 120 EU/m³ more endotoxin than did the IOM samples. Since the same gravimetric samples were analyzed for endotoxin content, the endotoxin difference is likely attributable to differences in endotoxin extraction. The prototype's disposable thin-film polycarbonate capsule was included with the filter in the 1-hr extraction procedure while the internal plastic cassette of the IOM required a rinse procedure that is susceptible to dust losses. Endotoxin concentrations measured with standard plastic IOM inserts that follow this rinsing procedure may underestimate the true endotoxin exposure concentrations. The maximum concentrations in the study (1.55 mg/m³ gravimetric, 2328 EU/m³ endotoxin) were lower than other agricultural or industrial environments. Future work should explore the performance of the prototype sampler in dustier environments, where concentrations approach particulates not otherwise specified (PNOS) limits of 10 mg/m³, including using the prototype as a personal sampler.     

Occupational exposure to trichloramine and trihalomethanes: adverse health effects among personnel in habilitation and rehabilitation swimming pools

Personnel in swimming pool facilities typically experience ocular, nasal, and respiratory symptoms due to water chlorination and consequent exposure to disinfection by-products in the air. The aim of the study was to investigate exposure to trichloramine and trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) from the perspective of adverse health effects on the personnel at Swedish habilitation and rehabilitation swimming pools. The study included 10 habilitation and rehabilitation swimming pool facilities in nine Swedish cities. The study population comprised 24 exposed swimming pool workers and 50 unexposed office workers. Personal and stationary measurements of trichloramine and trihalomethanes in air were performed at all the facilities. Questionnaires were distributed to exposed workers and referents. Spirometry, fraction of exhaled nitric oxide (FE_NO), and peak expiratory flow (PEF) were measured. Personal and stationary measurements yielded trichloramine levels of 1–76 µg/m³ (average: 19 µg/m³) and 1–140 µg/m³ (average: 23 µg/m³), respectively. A slightly higher, but not significant, prevalence of reported eye- and throat-related symptoms occurred among the exposed workers than among the referents. A significantly increased risk of at least one ocular symptom was attributed to trichloramine exposure above the median (20 µg/m³). Lung function (FVC and FEV1) was in the normal range according to the Swedish reference materials, and no significant change in lung function before and after shift could be established between the groups. Average FE_NO values were in the normal range in both groups, but the difference in the values between the exposed workers and referents showed a significant increase after shift. Hourly registered PEF values during the day of the investigation did not show any unusual individual variability. In conclusion, the increased risk of developing at least one ocular symptom at personal trichloramine concentrations over 20 µg/m³ combined with an increase in the difference in FE_NO during the work shift of the exposed workers should not be neglected as an increased risk of respiratory inflammation in the habilitation and rehabilitation swimming pool environment.     

Endotoxin Exposure and Respiratory Symptoms in the Cotton Textile Industry

One hundred fourteen male employees of a cotton spinning mill in western Germany participated in a cross-sectional study, the purpose of which was to clarify the dose effect of endotoxin exposure on respiratory symptoms. Airborne endotoxin exposures were classified as low (≤ 100 endotoxin units [EU]/m³), medium (> 100–450 EU/m³), or high (> 450 EU/m³), on the basis of endotoxin activity in the Limulus amoebocyte lysate assay. Age- and smoking-adjusted odds ratios (ORs) and confidence intervals (Cls) were estimated. The dose-response relationship between current endotoxin exposure and prevalence of wheezing (medium: OR = 2.15, 95% Cl = 0.48–9.62; high: OR = 5.49, 95% Cl = 1.17–25.81) and cough (medium: OR = 2.11; 95% Cl = 0.59–7.56; high: OR = 3.93; 95% Cl = 1.02–15.12) was significant (test for linear trend: p values = 0.020 and 0.040, respectively). The association between exposure and wheezing was stronger among atopic workers. The higher prevalence of chest tightness and shortness of breath among workers with medium and high current endotoxin exposure did not reach statistical significance. The results suggested that there was a dose-dependent increase in bronchial symptoms, with significant effects occurring at exposures that exceeded 450 EU/m³.     

Daily land use regression estimated woodsmoke and traffic pollution concentrations and the triggering of ST-elevation myocardial infarction: a case-crossover study

Prior work has reported acute associations between ST-elevation myocardial infarction (STEMI) and short-term increases in airborne particulate matter. Subsequently, the association between STEMI and hourly measures of Delta-C (marker of woodsmoke) and black carbon (marker of traffic pollution) measured at a central site in Rochester, NY, were examined, but no association was found. Therefore, land use regression estimates of Delta-C and black carbon concentrations at each patient’s residence were developed for 246 STEMI patients treated at the University of Rochester Medical Center during the winters of 2008–2012. Using case-crossover methods, the rate of STEMI associated with increased Delta-C and BC concentration on the same and previous 3 days was estimated after adjusting for 3-day mean temperature and relative humidity. Non-statistically significant increased rates of STEMI associated with interquartile range increases in concentrations of BC in the previous 2 days (1.10 μg/m³; OR?=?1.12; 95% CI 0.93, 1.35) and Delta-C in the previous 3 days (0.43 μg/m³; OR?=?1.16; 95% CI 0.96, 1.40) were found. Significantly increased rates of STEMI associated with interquartile range increases in concentrations of BC (1.23 μg/m³; OR?=?1.04; 95% CI?=?0.87, 1.24) or Delta-C (0.40 μg/m³; OR?=?0.94; 95% CI?=?0.85, 1.09) on the same day were not observed likely due, in part, to temporal misalignment. Therefore, sophisticated spatial-temporal models will be needed to minimize exposure error and bias by better predicting concentrations at individual locations for individual hours, especially for outcomes with short-term responses to air pollution (<?24 h).     

Acute respiratory health effects among cement factory workers in Tanzania: an evaluation of a simple health surveillance tool

Objectives: The effects of cement dust exposure on acute respiratory health were assessed among 51 high exposed and 33 low exposed male cement workers. The ability of the questionnaire to diagnose acute decrease in ventilatory function was also assessed. Methods: Acute respiratory symptoms were recorded by interview using a structured optimal symptom score questionnaire. Peak expiratory flow (PEF) was measured preshift and postshift for each worker with a Mini-Wright PEF meter. Personal respirable dust (n=30) and total dust (n=15) were measured with 37-mm Cyclone and 37-mm closed-faced Millipore cassette. Twenty-nine workers had concurrent respirable dust, PEF and questionnaire on the same day. Results: The geometric means of personal respirable dust and total dust among high exposed were 4.0 and 13.2 mg/m³, respectively, and 0.7 and 1.0 mg/m³ among low exposed. High exposed workers had more acute cough, shortness of breath and stuffy nose than the low exposed. Mean percentage cross-shift decrease in PEF was significantly more pronounced among high exposed workers than low exposed (95% CI 1.1, 6.1%). For workers with concurrent respirable dust, PEF and questionnaire assessment, an exposure–response relationship was found between log-transformed respirable dust and percentage cross-shift decrease in PEF (4.5% per unit of log-respirable dust in mg/m³ ; 95% CI 3.3, 5.6%). Respirable dust exposure ≥2.0 mg/m³ versus <2.0 mg/m³ was associated with increased prevalence ratio for cough (7.9) and shortness of breath (4.2). Shortness of breath was associated with the highest sensitivity (0.87) and specificity (0.83) for diagnosing a percentage cross-shift decrease in PEF of ≥10%. Conclusion: The observed acute respiratory health effects among the workers are most likely due to exposure to high concentrations of irritant cement dust. The results also highlight the usefulness of the questionnaire for health surveillance of the acute respiratory health effect.     

Association between lung function and exposure to smoke among firefighters at prescribed burns

We investigated the short-term effects of exposures to PM3.5, acrolein, formaldehyde, and carbon monoxide on lung function in a group of firefighters performing prescribed burns. Spirometric measurements were made on 65 firefighters at the beginning, midpoint, and end of their work shift, while exposure was measured over the entire day. The interquartile range (IQR) of daily personal PM3.5 exposures was 235 micrograms/m3 to 1317 micrograms/m3, with an average daily exposure of 882 micrograms/m3. Concentrations of acrolein (IQR: [0.002, 0.018] ppm), formaldehyde (IQR: [0.008, 0.085] ppm), and carbon monoxide (IQR: [2.10, 10.48] ppm) were similarly elevated. In this group of firefighters, FEV1 changed by -0.125 L from preshift to postshift (p < .001). We examined the association between this cross-shift lung function decrement and smoke exposure. A 1000 micrograms/m3 increase in PM3.5 was associated with a -0.030 L change in the cross-shift FEV1 (95% CI [-0.087, 0.026]). Acrolein, formaldehyde, and carbon monoxide exposure were also not significantly associated with changes in FEV1, FVC, or FEF25-75. We concluded that while firefighters' lung function significantly decreased from preshift to postshift, firefighters exposed to greater concentrations of respiratory irritants did not experience greater lung function decrements. We could not establish a significant link to any of the individual toxic components of smoke we measured.     

Personal inhalable dust and endotoxin exposure among workers in an integrated textile factory

Abstract

The aim of this study was to determine personal exposure to inhalable dust and endotoxin levels among workers in an integrated cotton-processing textile factory and exposure variability across the different work sections. Full shift measurements were carried out using inhalable conical samplers with 37?mm glass-fiber filters. Personal inhalable dust was determined gravimetrically, and endotoxin levels were analyzed by kinetic chromogenic Limulus Amebocytes Lysate assay. The geometric means of personal dust and endotoxin concentrations were 0.75?mg·m^?3 and 831 EU·m^?3, respectively. The highest dust and endotoxin concentrations were observed in carding section (1.34?mg·m^?3 and 6,381 EU·m^?3, respectively). Altogether, 11% of dust and 89% of endotoxin samples exceeded workplace exposure limits. This study showed a moderate correlation between inhalable dust and endotoxin (r?=?0.450, p?<?0.001). Our findings indicate that low dust exposure does not guarantee a low exposure to endotoxin.     

Exposure to dust,endotoxin and micro-organisms in the potato processing industry

Exposure to organic dust components was studied in four potato processing plants because preliminary results showed high exposures accompanied by work-related health complaints. Ambient air concentrations of inhalable dust ranged from below 0.4 up to 44 mg m⁻³ [geometric mean (GM) 0.64 mg m⁻³]. Respirable dust concentrations were considerably lower. Personal concentrations of inhalable dust were somewhat higher, and strongly related to a few working tasks dealing with dried starch or protein. Ambient air concentrations of endotoxin ranged from 0.5 to more than 60 000 endotoxin units (EU) per m³ for the inhalable size fraction (GM = 280 EU m⁻³). For the respirable size fraction, endotoxin concentrations were lower (about the same factor as for dust). Personal endotoxin concentrations were lower than ambient air concentrations, probably because workers did not work the whole period of the shift near endotoxin sources. Endotoxin exposure was evaluated as very high; 23% of the workers had a mean exposure above 1000 EU m⁻³ (100 ng m⁻³). Differences between plants had a large influence on both dust and endotoxin exposure. A fairly good correlation was found between counts of airborne gram-negative bacteria and airborne endotoxin of the respirable size fraction. Ambient air levels of bacteria and endotoxin were strongly related to process water temperature, suggesting that exposure reduction can be achieved by lowering this temperature or by other measures that inhibit bacterial growth. We conclude that recycling of process water probably constitutes an exposure source of bacteria and endotoxin in many facilities.     

Airborne Endotoxin Concentrations in Homes Burning Biomass Fuel

Background

About half of the world’s population is exposed to smoke from burning biomass fuels at home. The high airborne particulate levels in these homes and the health burden of exposure to this smoke are well described. Burning unprocessed biological material such as wood and dried animal dung may also produce high indoor endotoxin concentrations.

Objective

In this study we measured airborne endotoxin levels in homes burning different biomass fuels.

Methods

Air sampling was carried out in homes burning wood or dried animal dung in Nepal (n = 31) and wood, charcoal, or crop residues in Malawi (n = 38). Filters were analyzed for endotoxin content expressed as airborne endotoxin concentration and endotoxin per mass of airborne particulate.

Results

Airborne endotoxin concentrations were high. Averaged over 24 hr in Malawian homes, median concentrations of total inhalable endotoxin were 24 endotoxin units (EU)/m³ in charcoal-burning homes and 40 EU/m³ in wood-burning homes. Short cooking-time samples collected in Nepal produced median values of 43 EU/m³ in wood-burning homes and 365 EU/m³ in dung-burning homes, suggesting increasing endotoxin levels with decreasing energy levels in unprocessed solid fuels.

Conclusions

Airborne endotoxin concentrations in homes burning biomass fuels are orders of magnitude higher than those found in homes in developed countries where endotoxin exposure has been linked to respiratory illness in children. There is a need for work to identify the determinants of these high concentrations, interventions to reduce exposure, and health studies to examine the effects of these sustained, near-occupational levels of exposure experienced from early life.